More From Treasure Detectives

Valuable 'Barn Finds'

The term "barn find" rose to popularity and is often used to describe valuable cars that have been neglected in barns, gathering dust for decades. But the term can extend to mean any hidden treasure discovered in attics, cellars and closets. Collectibles with unbelievably high values can be stashed almost anywhere.

"The amazing thing [about barn finds] is they happen every day," said Curtis Dowling, art detective and host of the new CNBC Prime reality series "Treasure Detectives." "You'd imagine after all these years no one would have anything left."

So read on and take heed: If you don't use or sell off your valuables, your descendants will. And if you ever have to clean out a relative's house, always check the attic! Items that might not look like much can be pay dirt. One of the following discoveries turned out to be worth $70 million at auction.